1. Field
Apparatuses and methods consistent with the exemplary embodiments relate to an apparatus and a method of reproducing a multi image or mosaic, more particularly to a multi image reproducing apparatus and method, which are capable of reproducing each image content in accordance with its proper or natural frame update period, for example, at its frame rate, when simultaneously reproducing a plurality of image contents or images.
2. Description of the Related Art
Generally, an apparatus for reproducing a multi image (hereinafter, also referred to as “multi image reproducing apparatus”) is a device that simultaneously reproduces a plurality of image contents to display a multi image or mosaic on a screen of a display apparatus, such as a TV, and is used to monitor a plurality of image contents input from a plurality of external image sources in various fields, such as security, traffic, broadcasting, etc.
The multi image reproducing apparatus typically includes a content receptor, an image processor and an image composition and output part. The content receptor separates image data from each of a plurality of image contents input from a plurality of external image sources. The image processor processes the image data input from the content receptor to output the data by frames. The image composition and output part composes image frames input from the image processor and transmits the composed image frames to the display apparatus to be displayed as a multi image on a screen of a display apparatus.
However, in this conventional multi image reproducing apparatus, the image processor calculates output timings of the image frames for each content only in view of a frame rate of each image content without considering an image frame composition time and/or a frame update period of the image composition and output part and outputs the image frames to the image composition and output part at the calculated output timings.
As a result, the image frames output from the image processor to the image composition and output part are delayed for the image frame composition time of the image composition and output part based on output timing of a finally output image frame according to the frame rate of each image content, and then output to the display apparatus.
For instance, the frame rate ranges variously from 10 to 60 frames per second (FPS) depending on image content. Further, the frame update period FP of the image composition and output part is fixed to 3.3 to 40 milliseconds (ms) depending on performance of the multi image reproducing apparatus. Thus, as shown in FIG. 1, image frames input from the image processor to the image composition and output part between a first update time RPTi and a second update time RPTj in the frame update period FP of the image composition and output part are input at different input times IT1, IT2, . . . , ITN according to the frame rate of corresponding image contents. Accordingly, the image composition and output part starts composing the input frames after all image frames are input, composes the image frames for a predetermine image frame composition time CTi according to the image frames being composed, and outputs the composed frame to the display apparatus.
Here, if a time period ITN_RPTj from an input time ITN of the last image frame to the second frame update time RPTj of the image composition and output part is shorter than the image frame composition time CTi of the image composition and output part, an output time FPi of a composed image frame by the image composition and output part is a third update time RPTk, delayed by one period from the second update time RPTj as an ideal output time. Thus, the composed image frame is output at the third update time RPTk by the image composition and output part, skipping one frame update period, and displayed on the display apparatus for the output time FPi of the frame update period FP.
Here, an image frame of image data corresponding to image content input in a period P_RPTj (P<P_RPTj<RPTj) between a point P and the second update time RPTj among the plurality of image contents is delayed and output by the image frame composition time CTi at the image composition and output part, the point P being distant by the image frame composition time CT of the image composition and output part from the second update time RPTj towards the first update time RPTi. Thus, the image frame is output not at the second update time RPTj as the ideal output time but at the third update time RPTk along with the composed image frame, skipping one period update period, and is displayed on the display apparatus. If image frames exhibiting such a phenomenon frequently happen in one image content, an area on the screen of the display apparatus corresponding to the one image content provides discontinuous images to users instead of smooth images, resulting in deterioration in overall quality of images displayed on the screen of the display apparatus.